Most Helpful Guy
Remember that one of the things he might like about you is your inexperience. Some guys enjoy being the more experienced teacher with a less experienced girl "student." Most of the things that you do to express your feelings in a dating relationship are instinctive and you will not need any instruction or lessons.
Early on, if you say to him, "I'm glad that we are dating but I'm a little nervous because I've never done this before, so if there is anything that I do that seems a little strange, I hope you'll be patient and show me how to be a good girlfriend," you will win his heart.
However, if he wants to engage in sexual behaviors, do not give in to any pressure to do something that is contrary to your beliefs and values. You may lose a boyfriend by refusing to give in, but you will preserve your self-respect.
Most Helpful Girl
Just don't do anything you're not comfortable doing. Don't lie to your parents (this I learned from experience) about having a relationship because you probably won't be able to enjoy it out of fear.
I don't find being in a relationship any better or worse than being single. Dating is really just looking for someone to share experiences with. Don't stress. It should be fun!